This invention relates generally to spring coiling machines and spring forming processes. More particularly, the present invention relates to automated coiling machines for producing helical coil springs of various configurations and to the manufacturing of coil springs having tucked ends.
The basic construction and operating principles of spring coiling machines conventionally parallel those set forth in representative U.S. Pat. No. 2,119,002 issued on May 31, 1938, for a "Spring Coiling Machine", and U.S. Pat. No. 2,831,570 issued on Apr. 22, 1958, for "Wire Coiling Machine Having Cams for Holding The Feed Rolls Separated". The coiling machine described in U.S. Pat. No. 2,119,002 has features for permitting the operator to adjust the initial settings and cam-controlled movement of various tools and devices that determine the ultimate characteristics of the fabricated coil springs. The characteristics may include a uniform or variable spacing between turns and a uniform or variable turn diameter.
For a number of spring applications, it is desirable to tuck the leading and/or trailing ends of the coil spring. In some applications, it is desirable to have a coil spring wherein both ends of the spring are tucked so that the ends of the spring cannot interfere with the bearing surface of the closed or square end of the spring.
In conventional coiling machine operations, the leading end of the spring can be tucked by means of applying an initial tension to the formed spring. The leading end tuck may be accomplished at the coil forming station as the first and second coils are being formed by appropriate setting and operation of the coiling point and the pitch tool of the coiling machine.
However, in manufacturing processes wherein it is desired to also tuck the trailing end of the coil spring, the conventional spring coiling machines do not provide an efficient means for accomplishing the trailing end tuck operation at the coil forming station. The trailing end of the coil is conventionally tucked by first forming the coil spring, and then "kicking" in the end portions of the spring in a separate operation after the spring has been transferred from the spring coiler to another work station. Because the tucking process is essentially a separate manufacturing process, the manufacturing costs associated with coil springs having tucked ends and the difficulties in performing the tucking process result in significant costs and inefficiencies.